Conc is a software package that allows a Linux machine, or a group of
machines, to be used as a serial console concentrator. Each console
connected to the system may have its output logged, and clients
running either locally or on remote hosts may connect to any client.
Multiple connections to a single console line are permitted.

The systems consists of three components. The first
is concserv, the central
daemon, that keeps logs from all the consoles
and coordinates the rest of the system. When it
starts, concserv spawns
a number of termserv
processes that control the serial lines to
which the console lines are connected. The link
between a termserv and
concserv is encrypted and
termservs may run on separate
machines to concserv, communicated
over TCP/IP.

The final component, conc,
is the user interface. It connects to
concserv over an encrypted TCP/IP
link, and allows the system administrator to view the logs
of a particular machine, connect to its console, add and
remove consoles etc. There is also a small, text-based
interface called console that
allows connection to a single console.

Any number of user interface programs may run concurrently and
multiple connections to the same are possible, allowing groups
to work on one system. Having all the components communicate by
TCP/IP allows administration of machines from off site or unifying
management of co-located and local equipment.